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Support simple variable assignment

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This commit is contained in:
Eugen Wissner
2025-09-01 09:57:18 +02:00
parent 627975775c
commit 32b2e15bfd
8 changed files with 1467 additions and 430 deletions
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229
boot/stage5.elna
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@@ -2,14 +2,8 @@
# v. 2.0. If a copy of the MPL was not distributed with this file, You can
# obtain one at https://mozilla.org/MPL/2.0/.
# Stage3 compiler.
# Stage5 compiler.
#
# - Procedures without none or one argument.
# - Goto statements.
# - Character and integer literals.
# - Passing local variables to procedures.
# - Local variables should have the format: v00,
# where 00 is its offset from the sp register.
.section .rodata
@@ -64,23 +58,26 @@ asm_li: .string "\tli "
.type asm_lw, @object
asm_lw: .string "\tlw "
.type asm_la, @object
asm_la: .string "\tla "
.type asm_sw, @object
asm_sw: .string "\tsw "
.type asm_mv, @object
asm_mv: .string "mv "
.type asm_addi, @object
asm_addi: .string "\taddi "
.type asm_t0, @object
asm_t0: .string "t0"
.type asm_a0, @object
asm_a0: .string "a0"
.type asm_t1, @object
asm_t1: .string "t1"
.type asm_comma, @object
asm_comma: .string ", "
.type asm_sp, @object
asm_sp: .string "(sp)"
asm_sp: .string "sp"
.section .bss
@@ -257,7 +254,7 @@ begin
_is_upper();
sw a0, 4(sp)
_is_lower(v00);
_is_lower(v0);
lw t0, 0(sp)
xori t1, t0, '_'
@@ -289,10 +286,10 @@ proc _is_alnum();
begin
sw a0, 4(sp)
_is_alpha();
_is_alpha(v4);
sw a0, 0(sp)
_is_digit(v04);
_is_digit(v4);
lw a1, 0(sp)
or a0, a0, a1
@@ -413,12 +410,7 @@ end;
proc _write_token();
begin
sw a0, 0(sp)
la a0, source_code_position
lw a0, (a0)
lw a1, 0(sp)
_write_s();
_write_s(source_code_position, v0);
lw a0, 0(sp)
end;
@@ -491,7 +483,7 @@ begin
la a0, asm_li
_write_z();
la a0, asm_a0
la a0, asm_t0
_write_z();
la a0, asm_comma
@@ -509,7 +501,7 @@ begin
la a0, asm_li
_write_z();
la a0, asm_a0
la a0, asm_t0
_write_z();
la a0, asm_comma
@@ -542,23 +534,22 @@ end;
proc _compile_variable_expression();
begin
_compile_designator();
la a0, asm_lw
_write_z();
la a0, asm_a0
la a0, asm_t0
_write_z();
la a0, asm_comma
_write_z();
_advance_token(1);
_read_token();
_write_token();
_advance_token();
la a0, asm_sp
_write_c('(');
la a0, asm_t0
_write_z();
_write_c(')');
_write_c('\n');
end;
@@ -568,17 +559,15 @@ begin
la t0, source_code_position
lw t0, (t0)
lb a0, (t0)
sw a0, 0(sp)
li t1, '\''
beq a0, t1, .compile_expression_character_literal
li t1, 'v'
beq a0, t1, .compile_expression_variable
_is_digit();
_is_digit(v0);
bnez a0, .compile_expression_integer_literal
goto .compile_expression_end;
goto .compile_expression_variable;
.compile_expression_character_literal:
_compile_character_literal();
@@ -590,7 +579,7 @@ begin
.compile_expression_variable:
_compile_variable_expression();
goto .compile_expression_end;;
goto .compile_expression_end;
.compile_expression_end:
end;
@@ -604,11 +593,8 @@ begin
_read_token();
sw a0, 0(sp)
la t0, source_code_position
lw t0, (t0)
sw t0, 4(sp)
sw zero, 8(sp)
v4 := source_code_position;
v8 := 0;
# Skip the identifier and left paren.
addi a0, a0, 1
@@ -628,7 +614,7 @@ begin
la a0, asm_sw
_write_z();
la a0, asm_a0
la a0, asm_t0
_write_z();
la a0, asm_comma
@@ -642,8 +628,10 @@ begin
sub a0, t1, t0
_write_i();
_write_c('(')
la a0, asm_sp
_write_z();
_write_c(')')
_write_c('\n');
@@ -677,8 +665,7 @@ begin
_write_z();
_write_c('a');
lw a0, 8(sp)
_write_i();
_write_i(v8);
la a0, asm_comma
_write_z();
@@ -691,9 +678,11 @@ begin
sub a0, t1, t0
_write_i();
_write_c('(');
la a0, asm_sp
_write_z();
_write_c(')');
_write_c('\n');
goto .compile_call_finalize;
@@ -702,7 +691,7 @@ begin
la a0, asm_call
_write_z();
_write_s(v04, v00);
_write_s(v4, v0);
# Skip the right paren.
_advance_token(1);
@@ -718,10 +707,142 @@ begin
la a0, asm_j
_write_z();
_write_token(v00);
_write_token(v0);
_advance_token();
end;
proc _compile_local_designator();
begin
# Skip "v" in the local variable name.
_advance_token(1);
la a0, asm_addi
_write_z();
la a0, asm_t0
_write_z();
la a0, asm_comma
_write_z();
la a0, asm_sp
_write_z();
la a0, asm_comma
_write_z();
# Read local variable stack offset and save it.
v0 := source_code_position;
_read_token();
sw a0, 4(sp)
_write_token();
_advance_token();
_write_c('\n');
end;
proc _compile_global_designator();
begin
la a0, asm_la
_write_z();
la a0, asm_t0
_write_z();
la a0, asm_comma
_write_z();
_read_token();
_write_token();
_advance_token();
_write_c('\n');
end;
proc _compile_designator();
begin
la t0, source_code_position
lw t0, (t0)
lb a0, (t0)
li t1, 'v'
beq a0, t1, .compile_designator_local
goto .compile_designator_global;
.compile_designator_local:
_compile_local_designator();
goto .compile_designator_end;
.compile_designator_global:
_compile_global_designator();
goto .compile_designator_end;
.compile_designator_end:
end;
proc _compile_assignment();
begin
_compile_designator();
# Save the assignee address on the stack.
la a0, asm_sw
_write_z();
la a0, asm_t0
_write_z();
la a0, asm_comma
_write_z();
_write_i(20);
_write_c('(');
la a0, asm_sp
_write_z();
_write_c(')');
_write_c('\n');
# Skip the assignment sign (:=) with surrounding whitespaces.
_advance_token(4);
# Compile the assignment.
_compile_expression();
la a0, asm_lw
_write_z();
la a0, asm_t1
_write_z();
la a0, asm_comma
_write_z();
_write_i(20);
_write_c('(');
la a0, asm_sp
_write_z();
_write_c(')');
_write_c('\n');
la a0, asm_sw
_write_z();
la a0, asm_t0
_write_z();
la a0, asm_comma
_write_z();
_write_c('(');
la a0, asm_t1
_write_z();
_write_c(')');
end;
proc _compile_statement();
begin
# This is a call if the statement starts with an underscore.
@@ -737,6 +858,9 @@ begin
li t1, 'g'
beq t0, t1, .compile_statement_goto
li t1, 'v'
beq t0, t1, .compile_statement_assignment
_compile_line();
goto .compile_statement_end;
@@ -752,6 +876,12 @@ begin
goto .compile_statement_semicolon;
.compile_statement_assignment:
_advance_token(1);
_compile_assignment();
goto .compile_statement_semicolon;
.compile_statement_semicolon:
_advance_token(2);
@@ -789,13 +919,13 @@ begin
la a0, asm_type_directive
_write_z();
_write_token(v00);
_write_token(v0);
la a0, asm_type_function
_write_z();
# Write procedure label, _procedure_name:
_write_token(v00);
_write_token(v0);
la a0, asm_colon
_write_z();
@@ -834,9 +964,6 @@ begin
# Read the symbol type.
_read_token();
la t0, source_code_position
lw t0, (t0)
sw t0, 12(sp)
# Print the symbol type and newline.
addi a0, a0, 1